Conventionally, an aluminum substrate or a glass substrate is used as a substrate for a magnetic recording medium that is used in a hard disk drive. Such a substrate is manufactured through various surface treatment steps such as a polishing step on the surface, and after the surface treatment has been performed, a washing device is used to remove dust and the like that has adhered to the surface of the substrate.
As a washing device for a substrate for a magnetic recording medium, there is the example shown for example in Patent Document 1. In this example, a magnetic disk substrate or the like serves as the work, and after performing surface treatment such as a polishing step on the surface, in order to remove foreign matter or the like that adheres to the surface of the work, the works are washed using a liquid while being conveyed with a conveyor in a plurality of washing tanks.
Also, as shown in Patent Document 2, there is a device that washes works such as a substrate for a magnetic recording medium using a washing liquid in a washing tank. In this device, the washing liquid is discharged from the washing tank by causing the washing liquid to overflow.
[Patent Document 1] Japanese Unexamined Patent Application, First Publication No. 2001-96245
[Patent Document 2] Japanese Unexamined Patent Application, First Publication No. H06-31253